unixorn/git-extra-commands

#!/usr/bin/env bash
#
# Original source: https://github.com/jwiegley/git-scripts/blob/master/git-children-of

commit=$1
branch=$2

[ -z "$branch" ] && branch=HEAD

git rev-list --children "$branch" --not "$commit"^@ \
  awk "/^$commit/ { print \$2 }"